We propose to establish a primary care practice-based research network in the greater Houston area, including initially 30 practices, 240 primary care physicians, and an annual patient visit volume exceeding 750,000. This urban-based network will provide a laboratory for evaluating the effectiveness of primary care services delivered to the large, socioeconomically and ethnically diverse population of Houston (the 4th largest city in the US) and its surrounding communities. Unique aspects of this network include a significant representation of minority patients (African American, Hispanic, and Asian American); inclusion of clinical sites providing health care to the underserved and the homeless; family physicians, general internists, and general pediatricians; and involvement of a research team with experience in the use of electronic medical records for research and in developing and evaluating health care informatics and decision support tools. The Department of Family and Community Medicine, Baylor College of Medicine, will serve as the academic hub for this network. During the planning year, three organizations that provide the majority of the primary health care delivered in Harris County (which includes Houston) will work together to launch this network, including the following: 1) the Community Health Centers (CHCs) of the Harris County Hospital District; 2) Healthcare for the Homeless - Houston, Inc., and 3) Kelsey- Seybold Clinic. This one-year planning grant will form a planning committee and three complementary working groups. The planning committee will oversee coordination of the working groups, serve as liaison with the Center for Primary Care Research, explore sources of external funding, and develop the five-year business plan. The data management working group will address issues of existing data collection capabilities, web- based data collection, electronic data aggregation, integration of electronic medical records for research, and access and data security. The research methodology working group will address issues of common data elements, periodic reporting (eg, using NAMCS measures), use of existing evidence-based tools in practice, guidelines for data integrity, use of human subjects (ie, IRB approvals), and the design and implementation of primary care research projects involving network participants. The network development and communications working group will address issues of physician and practice recruitment and retention, incentives, and review and dissemination of new knowledge to network participants. The knowledge gained from this network should generalize to other, urban-based primary care settings, and help guide the translation of research into practice in settings serving socioeconomically and ethnically diverse patient populations.